Method of electric lighting.



WIETHOD UF ELECTRIC LIGHTING.

(Application led Oct. 10, 1901.)

(No Model.)

' UNirlEn @rares PATENT @tirreno PETER oOoPEE iHEWIEE, O'E NEW YORK, N. Y., AssieNon fro PETER 1 OOOPEE HEWITT, TRUSTEE, or NEW YORK, NY.

`Winti-ion or Ensor-Enc Eier-urine.

V I SPECIFICATION forming' part ot Lettere 19a/tent No., 690,953, dated January 14, 1902,. Original application filed April 18,1900, Serial No. 13,290. 'Divided and this application tiled October 10, 1901. Serial No. 78,157. No specimens.)

i ,of Electric Lighting, (which is a division of an application for Letters Patent filed by me April 18, 1900, Serial No. 13,290,) of which the following is a speciiication.

' My invention relates to thatI class of electric-lighting devices in which electric energy is transformed into light by its action upon E through which they pass.

gases or vapors inclosed in a suitable chamber with a suitable light-emittingelectrode. In the operation of lamps of the character referred to I have found that suitable gases having the proper density may be so affected by electric currents of moderate electromotive force as to yield light and cause the negative electrode to be heated to a high degree of incandesoence. A large portion of the resistance which a lamp of'thischaracter oiiers to the passageA of current is at the joint ofthe gas with the cathode'where the current enters the cathode, the gas also presenting considerable resistance. By suitablyadjusting these resistances the resistance at the cathode may be made such that the cathode will itself become heated to a high degree ofwincandescence, being itself near the center of the source of heat and emitting intense light.

`The relative amount of light developed in the vapor-path is small on account of the relatively short path of the current through the vapor, and a` certain portion of this vaporpath is occu pied by the dark space which su rrounds the negative electrode.

In operatinglamps with currents. ot' considerable quantity the electric current tends to pass around to the backof the cathode-and unless prevented is liable Vtosfnse the leading-in. conductors' and disintegrate the glass To prevent this, I provide a'prOtecting-covering for such portions of the electrode, leaving exposed onlyv those portions at which it is desired that the current shall enter. Y

In the accompanying drawings, Figure 1 illustrates one form of lamp, and Figs. 2 and 3a modification.

, electrode.

`of lamp may be varied.

Referring to the drawings, 1 represents the main body of' the lamp.

2 represents an electrode, in this instance the anode, located in the lower part of the lamp, and the cathode is represented at 5.

The electrodes may be made of suitable matenial-such, for instance, as iron orl other conducting material; but I may make the cathode of some light emissive material, such as rare earths or mixtures thereof, surrounding'the conductor leading the current to it.

The nature of the material of the cathode makes but little dierence with respect to its conductivity, as even when it is of a material which is a non-conductor when cold there is sufficient electric leakage into the lamp from the conductor leading into it (unless greatv care be taken to prevent it) to start the current, which when started Will heat the material by reason of 'its position at the negative The electrode2 is shown as being seated within a glass column 10,v which surrounds tlie leading-in wire 7; but the position of the positive electrode for this style The electrode 5 is shown as being seated within a tube 14 of porcelain or other suitable material, which is a, non-conductor and retains this quality when hot and is inert to electrical and chemical actions at the temperature to which it is subjected in the operation of thelamp. The cylinder 14 is shown as being carried by the stem or column 12 of glass through which the leading-in' wire 8 passes. The joints between the electrode and the porcelain and between the porcelain land the glass are suciently tight to prevent the electric current from passing through them and reaching the metal parts Within, thus forming an electrically-tight insulation over .the conductor leading through the walls of the vessel to the electrode.

With electrodes of the character described VI am able to operate the lamp so that the current Will pass to and from the electrodes and be prevented from, passing around to the portions near the leading-in conductors.

The lampillustrated in Fig. 1 is so constructed and its elements are so arranged that in the normal operation of the lamp the cathode'will be heated to a very high tempera-l ture, becoming itself a light-emitting body.

IOO

In this instance the electrode 5 is located at the'center of a globe 15, the anode 2 being carried in an extension 16. Gas ofthe proper density is placed Within the globe. l/Vhen the current traverses the lamp, considerable heat is generated at'the cathode 5, and the surrounding gas being, in a measure at least, a non-conductor of heat the temperature of the cathode 5 is maintained sufficiently high to be light-emissive. I have found, for instance, that with attenuated nitrogen contained Within the chamber and with iron electrodes separated a distance of about one and one-half inches, the lamp may be started with a direct current havinga pressure of seven hundred and fifty volts or less, and the resistance which the gas offers to the passage of the current and the resistance which is offered between the gas and th' cathode will render the lamp self-governing and pass a definite amount of electrical energy and convert it into light and heat, the heat being sufficient to maintain the cathode in a state of incandescence. f

It has been found that the resistance of a Vapor varies inversely With the current; but in the operation of mylamp in the case of an increase of current the consequent reduction of resistance in the vapor-path is compensated for-by an increased resistance at the cathode, and vice versa. This particular form of resistance isa phenomenon that takes place under proper adjustment when there is .no chemical or physical action at the negative electrode.

The feature'of self-regulation is important Whether the lamp be constructed to yield light merely through the instrumentality of the gas or by reason of the incandescence ot' the negative electrode, or both.

In this lamp the resistances at different points may be different at the time of starting from what they are When the lamp is running;I but by properly adjusting the gas density the lamp may bemado to start on the same current that it is designed to operate on.\

In Figs. 2 and 3 I have shown the inclosing case in the form of a globe, the cathodebeing surrounded by an anode 2, made in the form of a ring. The operation of this lamp is es- "sentially the same as already described with reference to Fig; 1.`

To bring about a condition where there is no physical or chemical change of state, it usually becomes necessary to electrically treat the lamp while on the pump, soas to produce such reactions as would be incidental tothe presence of minute quantities of impurities or `dirt inside the lamp due to im perfect'commercial manufacture. Having continued this until 11o-further reactions are apparentthe true vapor may be introduced into the lamp,

and its density varies untilthe desired result becomes apparent. l l

The means of cleaning and adJusting of density are more fully described in my Patsent resistance to the entrance of the electric.

current thereto, and by the passage of the current developing heat around the cathode, with a minimum development of light, and

,thereby heating the cathode and rendering it luminous. l

2. rThe method of maintaining ata constant resistance a gas or vapor lamp having a solidl cathode and a surrounding medium of gas or vapor, which consists in compensating for the increased resistance at the cathode under increments of current by a corresponding decrease of resistance in the gas or vapor.

The method ol adapting gas or vapor lamps to use upon circuits subject to slight variations of current,whichconsists in form-` .ing the conducting elementof the said lamp of a composite body partly solid land partly gaseous and so proportioning the density of the gas to the other conditions'of the lamp as to cause the gaseous element to compensate by a decreased resistance under increments of current, forA the normal increase in resistance at the solid element under the same conditions.

4. The method of transforming electrical energy into light through the instrumentality ICO of a lamp having a solid cathode and a surrounding medium of gas or vapor which consists in surrounding the cathode with a gas or vapor of such quality and density that the resistance of transition is very high, and by Rthe passage of the current utilizing the high transition resistance for the d evelopment of heat around the cathode, whereby the cathode is heated and rendered luminousf 5. The ymethod of` transforming electrical energy into light through the instrumentality of a lamp having two electrodes and an intervening gas or vapor, which consists in establishing such a physical condition of the gas or vapor at one electrode asto present resistl ance Vto the-entrance of the' electric current thereto, and by the passage of current developing heat around the cathode, and therebyv heating the'cathode and rendering it luminous.

Signed at New York, in the county of New York and State of New York, this 8th day of October, A. D. 1901,

PETER coorER` IIEWITT.

4 Witnesses WM. H. CAPEL, y i v GuE. CJHAPIN; g 

